Make body-less messages work, specifically 35=n

* Change DataDictionary class to also check the tag 35 enum when determining if msg type is valid
* Put some null-protection around calls to DataDictionary.Message [] accessor
* ATs of course
* Renamed 35=n to "XML_NON_FIX" in the tag 35 enum in all DD xmls

AcceptanceTest/ATApplication.cs

@@ -1,5 +1,6 @@
 using System.Collections.Generic;
 using QuickFix;
+using QuickFix.Fields;
 
 namespace AcceptanceTest
 {
@@ -110,6 +111,18 @@ private void ProcessNOS(Message message, SessionID sessionId)
             Session.SendToTarget(echo, sessionId);
         }
 
+        private void AcknowledgeXmlMessage(Message msg, SessionID sessionId) {
+            string beginString = Message.ExtractBeginString(msg.ToString());
+            string seqNo = msg.Header.GetString(34);
+
+            Message response = new();
+            response.Header.SetField(new BeginString(beginString));
+            response.Header.SetField(new MsgType("B"));
+            response.SetField(new Headline($"Successfully received 'n' message with seqNo={seqNo}"));
+            response.SetField(new NoLinesOfText(0));
+
+            Session.SendToTarget(response, sessionId);
+        }
 
         public void OnMessage(QuickFix.FIX41.News news, SessionID sessionId) { ProcessNews(news, sessionId); }
         public void OnMessage(QuickFix.FIX42.News news, SessionID sessionId) { ProcessNews(news, sessionId); }
@@ -173,8 +186,10 @@ public void FromApp(Message message, SessionID sessionId)
             }
         }
 
-        public void FromAdmin(Message message, SessionID sessionId)
-        { }
+        public void FromAdmin(Message message, SessionID sessionId) {
+            if (message.Header.GetString(35) == "n")
+                AcknowledgeXmlMessage(message, sessionId);
+        }
 
         public void ToAdmin(Message message, SessionID sessionId) { }
         public void ToApp(Message message, SessionID sessionId) { }

AcceptanceTest/ReflectorClient.cs

@@ -12,8 +12,8 @@ internal class ReflectorClient : IReflector
 {
     private static readonly Regex s_timeRegex = new(@"\<TIME([+-]\d+)\>", RegexOptions.Compiled);
     private static readonly Regex s_beginStringRegex = new(@"^8=.*?[\001]", RegexOptions.Compiled);
-    private static readonly Regex s_bodyLengthRegex = new(@"[\001]9=.*?[\001]", RegexOptions.Compiled);
-    private static readonly Regex s_checksumRegex = new(@"[\001]10=.*[\001]$", RegexOptions.Compiled);
+    private static readonly Regex s_bodyLengthRegex = new(@"^8=[^\001]*[\001]9=[^\001]*", RegexOptions.Compiled);
+    private static readonly Regex s_checksumRegex = new(@"[\001]10=[0-9]+[\001]$", RegexOptions.Compiled);
     private static readonly Dictionary<string, Regex> s_expectPatterns = new()
     {
         { "10", new Regex(@"\d{3}", RegexOptions.Compiled) },
@@ -217,4 +217,4 @@ public void Dispose()
     {
         ShutdownSocket();
     }
-}
+}

AcceptanceTest/definitions/server/fix43/ReceiveXmlMessage.def

@@ -0,0 +1,18 @@
+# Engine can receive complex type 'n' messages
+# and is not confused if the xml content contains SOH or FIX tags
+
+iCONNECT
+I8=FIX.4.3
35=A
34=1
49=TW
52=<TIME>
56=ISLD
98=0
108=6

+E8=FIX.4.3
35=A
34=1
49=ISLD
52=00000000-00:00:00.000
56=TW
98=0
108=6
10=0

+
+# Receive encapsulated ExecutionReport and get News response.
+# (Need the News response to ensure that FIX parses it and passes it up to the app;
+#  without this response, the test will false pass)
+I8=FIX.4.3
35=n
34=2
49=TW
52=<TIME>
56=ISLD
212=55
213=<RTRF>8=FIX.4.3
9=377
35=8
34=208
blah blah blah</RTRF>

+E8=FIX.4.3
35=B
34=2
49=ISLD
52=00000000-00:00:00.000
56=TW
33=0
148=Successfully received 'n' message with seqNo=2
10=0

+
+# logout message and response
+I8=FIX.4.3
35=5
34=3
49=TW
52=<TIME>
56=ISLD

+E8=FIX.4.3
35=5
34=3
49=ISLD
52=00000000-00:00:00.000
56=TW
10=0

+eDISCONNECT
+

AcceptanceTest/definitions/server/fix44/ReceiveXmlMessage.def

@@ -0,0 +1,18 @@
+# Engine can receive complex type 'n' messages
+# and is not confused if the xml content contains SOH or FIX tags
+
+iCONNECT
+I8=FIX.4.4
35=A
34=1
49=TW
52=<TIME>
56=ISLD
98=0
108=6

+E8=FIX.4.4
35=A
34=1
49=ISLD
52=00000000-00:00:00.000
56=TW
98=0
108=6
10=0

+
+# Receive encapsulated ExecutionReport and get News response.
+# (Need the News response to ensure that FIX parses it and passes it up to the app;
+#  without this response, the test will false pass)
+I8=FIX.4.4
35=n
34=2
49=TW
52=<TIME>
56=ISLD
212=55
213=<RTRF>8=FIX.4.3
9=377
35=8
34=208
blah blah blah</RTRF>

+E8=FIX.4.4
35=B
34=2
49=ISLD
52=00000000-00:00:00.000
56=TW
33=0
148=Successfully received 'n' message with seqNo=2
10=0

+
+# logout message and response
+I8=FIX.4.4
35=5
34=3
49=TW
52=<TIME>
56=ISLD

+E8=FIX.4.4
35=5
34=3
49=ISLD
52=00000000-00:00:00.000
56=TW
10=0

+eDISCONNECT
+

AcceptanceTest/definitions/server/fix50/ReceiveXmlMessage.def

@@ -0,0 +1,18 @@
+# Engine can receive complex type 'n' messages
+# and is not confused if the xml content contains SOH or FIX tags
+
+iCONNECT
+I8=FIXT.1.1
35=A
34=1
49=TW
52=<TIME>
56=ISLD
98=0
108=6
1137=7

+E8=FIXT.1.1
35=A
34=1
49=ISLD
52=00000000-00:00:00.000
56=TW
98=0
108=6
1137=7
10=0

+
+# Receive encapsulated ExecutionReport and get News response.
+# (Need the News response to ensure that FIX parses it and passes it up to the app;
+#  without this response, the test will false pass)
+I8=FIXT.1.1
35=n
34=2
49=TW
52=<TIME>
56=ISLD
212=55
213=<RTRF>8=FIX.4.3
9=377
35=8
34=208
blah blah blah</RTRF>

+E8=FIXT.1.1
35=B
34=2
49=ISLD
52=00000000-00:00:00.000
56=TW
33=0
148=Successfully received 'n' message with seqNo=2
10=0

+
+# logout message and response
+I8=FIXT.1.1
35=5
34=3
49=TW
52=<TIME>
56=ISLD

+E8=FIXT.1.1
35=5
34=3
49=ISLD
52=00000000-00:00:00.000
56=TW
10=0

+eDISCONNECT
+

AcceptanceTest/definitions/server/fix50sp1/ReceiveXmlMessage.def

@@ -0,0 +1,18 @@
+# Engine can receive complex type 'n' messages
+# and is not confused if the xml content contains SOH or FIX tags
+
+iCONNECT
+I8=FIXT.1.1
35=A
34=1
49=TW
52=<TIME>
56=ISLD
98=0
108=6
1137=8

+E8=FIXT.1.1
35=A
34=1
49=ISLD
52=00000000-00:00:00.000
56=TW
98=0
108=6
1137=8
10=0

+
+# Receive encapsulated ExecutionReport and get News response.
+# (Need the News response to ensure that FIX parses it and passes it up to the app;
+#  without this response, the test will false pass)
+I8=FIXT.1.1
35=n
34=2
49=TW
52=<TIME>
56=ISLD
212=55
213=<RTRF>8=FIX.4.3
9=377
35=8
34=208
blah blah blah</RTRF>

+E8=FIXT.1.1
35=B
34=2
49=ISLD
52=00000000-00:00:00.000
56=TW
33=0
148=Successfully received 'n' message with seqNo=2
10=0

+
+# logout message and response
+I8=FIXT.1.1
35=5
34=3
49=TW
52=<TIME>
56=ISLD

+E8=FIXT.1.1
35=5
34=3
49=ISLD
52=00000000-00:00:00.000
56=TW
10=0

+eDISCONNECT
+

AcceptanceTest/definitions/server/fix50sp2/ReceiveXmlMessage.def

@@ -0,0 +1,18 @@
+# Engine can receive complex type 'n' messages
+# and is not confused if the xml content contains SOH or FIX tags
+
+iCONNECT
+I8=FIXT.1.1
35=A
34=1
49=TW
52=<TIME>
56=ISLD
98=0
108=6
1137=9

+E8=FIXT.1.1
35=A
34=1
49=ISLD
52=00000000-00:00:00.000
56=TW
98=0
108=6
1137=9
10=0

+
+# Receive encapsulated ExecutionReport and get News response.
+# (Need the News response to ensure that FIX parses it and passes it up to the app;
+#  without this response, the test will false pass)
+I8=FIXT.1.1
35=n
34=2
49=TW
52=<TIME>
56=ISLD
212=55
213=<RTRF>8=FIX.4.3
9=377
35=8
34=208
blah blah blah</RTRF>

+E8=FIXT.1.1
35=B
34=2
49=ISLD
52=00000000-00:00:00.000
56=TW
33=0
148=Successfully received 'n' message with seqNo=2
10=0

+
+# logout message and response
+I8=FIXT.1.1
35=5
34=3
49=TW
52=<TIME>
56=ISLD

+E8=FIXT.1.1
35=5
34=3
49=ISLD
52=00000000-00:00:00.000
56=TW
10=0

+eDISCONNECT
+

QuickFIXn/DataDictionary/DataDictionary.cs

@@ -15,9 +15,12 @@ public class DataDictionary
         public string? MajorVersion { get; private set; }
         public string? MinorVersion { get; private set; }
         public string? Version { get; private set; }
-        public readonly Dictionary<int, DDField> FieldsByTag = new();
-        public readonly Dictionary<string, DDField> FieldsByName = new();
+
         public readonly Dictionary<string, DDMap> Messages = new();
+        public readonly Dictionary<string, DDField> FieldsByName = new();
+
+        // TODO: Audit these Dict usages for unprotected [] lookups.
+        public readonly Dictionary<int, DDField> FieldsByTag = new();
         private readonly Dictionary<string, XmlNode> _componentsByName = new();
 
         public bool CheckFieldsOutOfOrder { get; set; }
@@ -118,10 +121,19 @@ public static void CheckHasNoRepeatedTags(FieldMap map)
                 : null;
         }
 
+        /// <summary>
+        /// If DD defines this message type, returns with no side effect; else throws InvalidMessageType.
+        /// </summary>
+        /// <param name="msgType"></param>
+        /// <exception cref="InvalidMessageType"></exception>
         public void CheckMsgType(string msgType)
         {
-            if (!Messages.ContainsKey(msgType))
-                throw new InvalidMessageType();
+            if (Messages.ContainsKey(msgType))
+                return;
+            if (FieldsByTag[35].EnumDict.ContainsKey(msgType))
+                return;
+            throw new InvalidMessageType();
+
         }
 
         public void CheckHasRequired(Message message, string msgType)
@@ -138,10 +150,13 @@ public void CheckHasRequired(Message message, string msgType)
                     throw new RequiredTagMissing(field);
             }
 
-            foreach (int field in Messages[msgType].ReqFields)
+            if (Messages.TryGetValue(msgType, out DDMap? ddmap))
             {
-                if (!message.IsSetField(field))
-                    throw new RequiredTagMissing(field);
+                foreach (int field in ddmap.ReqFields)
+                {
+                    if (!message.IsSetField(field))
+                        throw new RequiredTagMissing(field);
+                }
             }
 
             /* FIXME TODO group stuff
@@ -183,13 +198,23 @@ public void Iterate(FieldMap map, string msgType)
             }
 
             // check contents of each group
-            foreach (int groupTag in map.GetGroupTags())
-            {
-                for (int i = 1; i <= map.GroupCount(groupTag); i++)
+            List<int> groupTagList = map.GetGroupTags();
+            if (groupTagList.Count > 0) {
+                if (!Messages.TryGetValue(msgType, out DDMap? msgDdMap))
                 {
-                    Group g = map.GetGroup(i, groupTag);
-                    DDGrp ddg = this.Messages[msgType].GetGroup(groupTag);
-                    IterateGroup(g, ddg, msgType);
+                    // This shouldn't be possible
+                    throw new MessageParseError(
+                        $"Cannot locate msgType='{msgType}' message groups in DataDictionary (Please report this error)");
+                }
+
+                foreach (int groupTag in groupTagList)
+                {
+                    for (int i = 1; i <= map.GroupCount(groupTag); i++)
+                    {
+                        Group g = map.GetGroup(i, groupTag);
+                        DDGrp ddg = msgDdMap.GetGroup(groupTag);
+                        IterateGroup(g, ddg, msgType);
+                    }
                 }
             }
         }

QuickFIXn/Fields/Fields.cs

@@ -709,7 +709,7 @@ public MsgType(string val)
         public const string BID_REQUEST = "k";
         public const string BID_RESPONSE = "l";
         public const string LIST_STRIKE_PRICE = "m";
-        public const string XML_MESSAGE = "n";
+        public const string XML_NON_FIX = "n";
         public const string REGISTRATION_INSTRUCTIONS = "o";
         public const string REGISTRATION_INSTRUCTIONS_RESPONSE = "p";
         public const string ORDER_MASS_CANCEL_REQUEST = "q";
@@ -859,7 +859,6 @@ public MsgType(string val)
         public const string BIDREQUEST = "k";
         public const string BIDRESPONSE = "l";
         public const string LISTSTRIKEPRICE = "m";
-        public const string XML_NON_FIX = "n";
         public const string REGISTRATIONINSTRUCTIONS = "o";
         public const string REGISTRATIONINSTRUCTIONSRESPONSE = "p";
         public const string ORDERMASSCANCELREQUEST = "q";

RELEASE_NOTES.md

@@ -45,6 +45,7 @@ What's New
 * #900 - correct CompositeLog to use IFactory.CreateNonSessionLog when appropriate (gbirchmeier)
 * #891 - make NonSessionLog implement IDisposable and fix the IOException (VAllens)
 * #893 - Upgrade the unit testing framework to the latest version and remove obsolete Assert methods (VAllens)
+* #900 - A fix to make body-less messages work, specifically 35=n aka XMLnonFIX (gbirchmeier)
 
 ### v1.12.0
 

UnitTests/DataDictionaryTests.cs

@@ -373,6 +373,21 @@ public void ParseThroughComments()
             Assert.That(news.GetGroup(33).IsField(355), Is.True); // EncodedText
         }
 
+        [Test]
+        public void TestCheckMsgType() {
+            DataDictionary dd = new DataDictionary();
+            dd.LoadFIXSpec("FIX44");
+
+            Assert.Throws(typeof(InvalidMessageType), delegate { dd.CheckMsgType("foo"); });
+
+            // True check, case 1: DD has a <message> definition for this one
+            Assert.DoesNotThrow(delegate { dd.CheckMsgType("B"); });
+
+            // True check, case 2: Type is in field 35, but there is no Message type
+            Assert.That(dd.Messages, Does.Not.ContainKey("n")); // Sanity check; if fails, fix the test.
+            Assert.DoesNotThrow(delegate { dd.CheckMsgType("n"); });
+        }
+
         private static XmlNode MakeNode(string xmlString)
         {
             XmlDocument doc = new XmlDocument();

spec/fix/FIX43.xml

@@ -2404,7 +2404,7 @@
       <value enum="k" description="BID_REQUEST" />
       <value enum="l" description="BID_RESPONSE" />
       <value enum="m" description="LIST_STRIKE_PRICE" />
-      <value enum="n" description="XML_MESSAGE" />
+      <value enum="n" description="XML_NON_FIX" />
       <value enum="o" description="REGISTRATION_INSTRUCTIONS" />
       <value enum="p" description="REGISTRATION_INSTRUCTIONS_RESPONSE" />
       <value enum="q" description="ORDER_MASS_CANCEL_REQUEST" />

spec/fix/FIX44.xml

@@ -4160,7 +4160,7 @@
       <value enum="k" description="BID_REQUEST" />
       <value enum="l" description="BID_RESPONSE" />
       <value enum="m" description="LIST_STRIKE_PRICE" />
-      <value enum="n" description="XML_MESSAGE" />
+      <value enum="n" description="XML_NON_FIX" />
       <value enum="o" description="REGISTRATION_INSTRUCTIONS" />
       <value enum="p" description="REGISTRATION_INSTRUCTIONS_RESPONSE" />
       <value enum="q" description="ORDER_MASS_CANCEL_REQUEST" />

spec/fix/FIX50.xml

@@ -4647,7 +4647,7 @@
    <value enum='L' description='LIST_EXECUTE' />
    <value enum='m' description='LIST_STRIKE_PRICE' />
    <value enum='M' description='LIST_STATUS_REQUEST' />
-   <value enum='n' description='XML_MESSAGE' />
+   <value enum='n' description='XML_NON_FIX' />
    <value enum='N' description='LIST_STATUS' />
    <value enum='o' description='REGISTRATION_INSTRUCTIONS' />
    <value enum='p' description='REGISTRATION_INSTRUCTIONS_RESPONSE' />

spec/fix/FIX50SP1.xml

@@ -5382,7 +5382,7 @@
    <value enum='L' description='LIST_EXECUTE' />
    <value enum='m' description='LIST_STRIKE_PRICE' />
    <value enum='M' description='LIST_STATUS_REQUEST' />
-   <value enum='n' description='XML_MESSAGE' />
+   <value enum='n' description='XML_NON_FIX' />
    <value enum='N' description='LIST_STATUS' />
    <value enum='o' description='REGISTRATION_INSTRUCTIONS' />
    <value enum='p' description='REGISTRATION_INSTRUCTIONS_RESPONSE' />

spec/fix/FIXT11.xml

@@ -152,7 +152,7 @@
       <value enum='k' description='BID_REQUEST'/>
       <value enum='l' description='BID_RESPONSE'/>
       <value enum='m' description='LIST_STRIKE_PRICE'/>
-      <value enum='n' description='XML_MESSAGE'/>
+      <value enum='n' description='XML_NON_FIX'/>
       <value enum='o' description='REGISTRATION_INSTRUCTIONS'/>
       <value enum='p' description='REGISTRATION_INSTRUCTIONS_RESPONSE'/>
       <value enum='q' description='ORDER_MASS_CANCEL_REQUEST'/>